Hi, I tried on other places asking for help but it looks like noone knew how to fix it without a format =/

So here's the short story.
I had a perfect driver, it worked fine, I had a really good framerate...
But it came one day, that I wanted to try the evil colin mcrae rally 2.0, and I saw it would require an older driver or an special omega driver (because the newest driver just freeze the game =/), so I decided to try the omega driver, but why...
The game worked, but it was too slow, I tried other games and the frames droped alot :O (like 25fps), 3Dmark scored 400 points less so I decided to uninstall the driver and install the older one, but it didn't fixed '-', I still get a low fps and not the older fps that were high...

So what should I do to go back to the original performance? D:

spec:
-windows 98se
-pentium mmx 233MHz w 1mb cache l2
-128mb sdram
-3DFX voodoo 3 3000
-80gb hd

The only thing I don't want is to format it again,it's really slow to resurrect the floppy drive to install windows D: